Attracting a pair of bluebirds to your nest box and having them fledge a brood of young bluebirds is an amazing accomplishment. If you’ve done this, congratulations! You’re a successful bluebird landlord. My first year with bluebirds, we had just one nesting pair, and I was content with that. But after they all flew away and we cleaned out the nest box for winter, I started to wonder if the same pair would come back the following year.
So, do bluebirds return to the same nest box every year? Some bluebirds do return, and others don’t. According to two different studies, 26% – 44% of adult bluebirds return to breed at the same site where they nested the previous year. Therefore, there is about a one in three chance that the bluebirds you have in your nest box this year will return to the same box the following year.
The above photo by Dolan Trout is licensed under CC BY 2.0
What Factors Make Bluebirds More Likely To Return To The Same Nest Box?
The likelihood that a pair of bluebirds will return to the same nest box the following year is higher under the following conditions:
1. If the bluebirds have successfully nested in your nest box before
If a pair of bluebirds has successfully used your nest box before, then they are more likely to return to the same area the following year. Successful nesters are also likely to seek out the exact same nest box that they used the previous year (source).
Sounds simple then, doesn’t it? Attract bluebirds one year, let them raise their young, and they’ll keep coming back to the same bird house. Unfortunately, it’s not that easy. Just because bluebirds produce a successful brood in a certain nest box one year, this doesn’t absolutely guarantee that they will return to the same box the following year, but it does encourage them to do so!
Basically, if a pair of bluebirds finds your nest box, and they know that it’s a good place to raise a family, it gives them a good reason to come back again. That’s why I definitely recommend using a good quality nest box that’s designed to the specifications that bluebirds require. Check out my Recommended Tools page to see the nest boxes that I use and recommend.
2. If the bluebirds are older
Older bluebird pairs are more likely to return to the same next box year after year than younger bluebird pairs. This is likely due to older male bluebirds having more firmly established breeding territories than younger birds. So if your bluebirds are on the older side (from 3-6 years old), it increases their chances of returning.
Sadly, there’s not really a great way to tell the age of a bluebird, unless you have a lot of experience with birdwatching. But, just know that the age of your bluebirds could be a deciding factor on whether or not they choose to return. Older birds seem to return more often.
3. If there is low competition for the nest box
Bluebirds are territorial creatures, and won’t typically build a nest less than 100 yards away from another pair of bluebirds. They also experience competition from house sparrows, house wrens, and other cavity nesting birds. Since bluebirds are seeking the path of least resistance, competition will be a deciding factor when choosing whether or not to return to a nesting site. Overall, if bluebirds experience low competition for a certain nest box, this increases their chances of choosing that nest box again.
As bluebirds populations are now increasing, (see the article I wrote about bluebird populations here) competition between bluebirds will naturally be increasing in certain areas too. In highly competitive areas, bluebirds will have to compete with other bluebirds for nest boxes and for food during the nesting season. Therefore, even if a pair of bluebirds wants to return to the same nest box where they nested last year, they might choose to move on to a new area with lower competition if they can find one.
What Factors Keep Bluebirds From Returning To The Same Nest Box?
Photo by ibm4381 is licensed under CC BY 2.0
If any of the following factors are true, your bluebirds are less likely to return to the same nest box the following year:
1. If bluebirds have had failed nesting attempts in your nest box
Failed nesting attempts are discouraging for bluebirds. Studies show that bluebirds are less likely to return to a nest box the following year if something went wrong at that nest box and they weren’t able to fledge young (source).
Maybe your bluebirds got driven away by house sparrows or their eggs were destroyed by a house wren. Their nest could have become infested with blowfly larvae, killing the young. Maybe the nest box got too hot during a heatwave and the baby birds didn’t make it. There are a number of reasons that nests don’t succeed, and after unfortunate circumstances like these, bluebirds are slightly more likely to go looking for a new nesting site the next year.
2. If the bluebirds are young
Early in their lives, young bluebirds tend to travel to a new area so that they don’t end up breeding too close to where they were born. Studies show that female eastern bluebirds may travel up to 12 miles away during this “dispersion” period, and males may go up to 3 miles away (source). This means that young bluebirds probably won’t end up nesting in the same nest box where they were hatched.
Also, younger bluebirds tend to start breeding later in the season than older bluebirds. If a young male bluebird has his eyes on a particular nest box, an older male bluebird might beat him to it. So, even if a young bluebird pair successfully nests in your bluebird house during a season, they will be less likely than an older bluebird pair to return to that exact nest box the following year.
3. If there is high competition from other bluebirds
If there is a relatively high concentration of bluebirds in a particular area, bluebirds will be slightly less likely to return to the same nest box year-over-year. They are going to seek a new nest box or natural cavity in a less competitive area.
This is a natural occurrence, since bluebirds, like other creatures, want to follow the path of least resistance. The path of least resistance for bluebirds usually means finding new, open land with low competition.
It’s not just competition from other bluebirds that influences a bluebird’s decision on where to nest…
4. If there is high competition from other species
When there is high competition from other birds, like house sparrows, wrens, tree swallows, etc. bluebirds will be less likely to return to the same nest box as the year before. If bluebirds are constantly being harassed by sparrows, or if there’s simply too much competition in the area from wrens or swallows, the bluebirds will look for a nest box in an area with lower competition.
Conclusion
Technically, there is only a one in three chance that the same pair of bluebirds will return to your nest box every year, but that doesn’t mean you can’t still attract bluebirds to your backyard and be a great bluebird landlord!
If you set up your nest box in a good location, monitor it consistently, and protect the nest box from predators, you’ll be very likely to have some pair of bluebirds nesting there every single year.
If you need a new nest box for your backyard, check out my Recommended Tools page to see the bluebird houses that I recommend.